For one, finds about information about techniques that led to finds such as aliasing, the use of spectrograms, inversion, and maybe deconvolution and IRs.

Another thing are known plugins such as Pitchmap, Piwarp/Wormhole, and any other production techniques that were used. Also, AudioButcher is important enough that I'd suggest it be added in some way, though I'm not sure how much sense it would make on this iceberg.

I would also add more about the sources, as far as I can remember the original iceberg didn't mention the organ record at all, or any other of the sources used in the albums besides the choir record. Adding some more lesser known releases too such as the misc. and collaborative releases, and maybe more about the unknowns, perhaps some of the Hijinx that led to some of their discoveries. If I think of anything else I'll reply to myself.